The investigation marks a change of course for House Republicans, who previously avoided direct involvement with the inquiry into the private server Clinton used as secretary of State. Instead, they had let the FBI take the lead on investigating issues related to the machine, likely as a way to avoid the political firestorm sure to erupt should Republicans focus their energies on the top Democrat.

“Certainly the FBI, they should do their investigation,” said Rep. Jim Jordan (R-Ohio), a member of the Oversight Committee who supports the new effort.

The panel will look into how Clinton determined that only roughly half of her 60,000 emails were work-related, he indicated, and will ask questions about the State Department’s process for reviewing federal records.

“There are all kinds of questions — and again, not just about Secretary Clinton, but in general,” Jordan said. “So of course that’s something we should look at.”

The strategy has political risks, given lingering concerns that House Republicans unfairly injected themselves into the 2016 campaign by launching a special panel on Benghazi.

“One tax-payer funded congressional committee dedicated to attacking Secretary Clinton was one too many, and the opening of a new investigation worsens the already damaging precedent of using the Congress’s investigative powers to damage a presidential candidate,” Rep. Adam Schiff (D-Calif.), the top Democrat on the House Intelligence Committee and a supporter of Clinton's presidential bid, said in a statement.

The new probe, Schiff added, is an attempt to “smear” Clinton and “is better left to the Republican National Committee, not a taxpayer-funded congressional committee.”

Last year, a remark from House Majority Leader Kevin McCarthy (R-Calif.) that linked the House Select Committee on Benghazi to Clinton's poll numbers caused uproar in both parties and hurt McCarthy's bid for Speaker.

“Everything that Republicans do or Democrats do will be viewed as partisan,” Rep. Darrell Issa (R-Calif.), the former Oversight Committee chairman, said this week.

Issa appeared unaware of Chaffetz’s new probe. Like many Republicans approached this week by The Hill, he suggested that lawmakers ought to stand back and let the FBI conduct its work. The federal investigators are looking into the security of the unorthodox email setup and whether any classified information was mishandled.

“We’re in a highly political season and as a result, are appropriately urging the FBI to expeditiously make its decision about culpability,” he said, “because there obviously are documents that could not accidentally have been created.”

House Intelligence Committee Chairman Devin Nunes (R-Calif.) agreed. His committee has been briefed throughout the FBI’s investigation.

“FBI is the lead, and we have to continue to monitor as things come forward at this point,” Nunes told The Hill on Wednesday. “We have to get all the data before you take another step.”

Chaffetz told The Hill there "shouldn't be" any concerns about partisanship with his investigation. The Federal Records Act and Freedom of Information Act give the committee jurisdiction in the matter, he added.

On Friday, the State Department declared that 22 emails on Clinton’s server were being classified as “top secret,” the highest level of government classification, and would not be released to the public, even in redacted form. The top secret designation comes on top of more than 1,300 emails that have previously been classified at lower levels.

The emails were not marked as classified when sent, the government has maintained. However, that does not necessarily mean that they were not classified at the time. The State Department also said it is looking into whether the emails should have been classified top secret at the time they were exchanged.

News of the high classification intensified fears that Clinton’s bespoke email arrangement may have jeopardized national security by making American secrets vulnerable to foreign hackers.

The revelation appeared to spur House Oversight Republicans to reconsider whether the committee should be playing a role in the investigation.

“It’s troubling when State Department believes that, at a minimum, 22 of those emails were considered to be top secret, and the response is that it wasn’t top secret at the time.” said Hurd, who spent many years as an undercover CIA agent. “Having spent almost my entire adult life in the intelligence world, I don’t know too many situations in which information became top secret after the fact.”

“The men and women of the FBI, they’re to be nonpartisan and investigate crimes,” said Hurd. “And if a crime is committed, I think the FBI, it’s their duty to bring that to the right folks attention.”

Critics of Clinton have urged for the Justice Department to file federal charges against her, though that appears unlikely.

Chaffetz's move seems to be a rapid change of course in Republicans’ effort.

The House Science Committee had launched an initial inquiry into the security of Clinton’s email arrangement last month but appeared to be rebuked by GOP leadership. Clinton’s emails were best left to the FBI, leaders indicated, or else to the Benghazi Committee, which is reviewing the messages related to the 2012 terror attacks on a U.S. compound in Libya.

Smith’s committee has letters out to four companies that played roles in maintaining and protecting Clinton’s personal server.

“I’ll let you know when we get to the next step,” he told The Hill on Tuesday. “We’re in the process now of waiting to hear from the companies we wrote the letter to. I hope to know in coming days.”

With the news of the Oversight inquiry and the 22 top secret emails, though, Smith has decided to temporarily pause his investigation.

“The committee temporarily will defer to the FBI’s expanding investigation,” a committee aide told The Hill on Thursday morning. “We expect the FBI to do its job and fully investigate cyber vulnerabilities that may have resulted from former Secretary Clinton’s decision to deviate from established cybersecurity standards and requirements.”